It would be nice to be able to add more contact information to a person/user to help with reconciling their user profile on the WP side but, also to help with users who maybe use multiple emails or phone numbers (i.e. When I use my personal email on my directory information I receive a warning that it doesn’t match the email on my WP user profile but, that shouldn’t really matter IMO.).
On the user’s side, it would make sense for them to be able to create a WP account using any email address they desire and have that added to the directory as a secondary/primary contact method (Maybe they could be offered the choice?).
Along with this, I think it would be beneficial to be able to add/remove specific contact information for a person from the directory.
For example, if a person has two email addresses each address could contain a checkbox that says “Include in the directory” and each one would be listed under that person.